1. Field
The present invention relates generally to an improved data processing system and, in particular, to a method and apparatus for processing information. Still more particularly, the present disclosure relates to a method and apparatus for caching information in a network data processing system.
2. Description of the Related Art
A cache memory is readily and rapidly accessible by a CPU and retains data that is likely to be needed later. Consequently, a cache improves performance in processing information in data processing systems, because future requests for the data can be satisfied and processed more quickly.
For example, the data in the cache may have been computed at an earlier time. Alternatively, the data in the cache may include duplicates of data that were previously retrieved from another storage location that is much slower to access than the cache. If this data is requested again at a later time and present in the cache, the request can be satisfied by reading the data from the cache. This process is faster than re-computing the data (even if the cache is disk storage) and faster than re-retrieving the data from the other storage location (if the cache, such as RAM or flash memory, is more readily and rapidly accessible than the other storage device).
As another example, if a user at a client computer requests a web page, a web server application may request the web page from storage or dynamically generate the web page from information in storage. This web page may then be stored in a cache at the web server. If the same web page is requested again, the web page may be more quickly accessed from the cache than from more slowly-accessible storage or by re-generating the web page. Even if the cache comprises disk storage, this will be more quickly available than if the web page has to be regenerated.